Multi-pair data cable with configurable core filling and pair separation

ABSTRACT

An improved data telecommunications cable according to the invention includes a plurality of twisted pairs of insulated conductors, and a substantially flat configurable dielectric separator disposed between the plurality of twisted pairs of insulated conductors along a longitudinal length of the telecommunications cable. The data communications cable also includes a jacket assembly enclosing the plurality of twisted pairs of insulated conductors and the substantially flat dielectric pair separator. The substantially flat dielectric pair separator separates each twisted pair of insulated conductors from every other twisted pair of insulated conductors with a spacing sufficient to provide a desired crosstalk isolation between each of the plurality of twisted pairs of insulated conductors.

RELATED APPLICATION

This application is a Continuation of under 35 U.S.C. §120 to,commonly-owned, U.S. patent application Ser. No. 09/853,512, filed May11, 2001 now U.S. Pat. No. 6,570,095, entitled Multi-Pair Data Cablewith Configurable Core Filling and Pair Separation which is acontinuation under 35 U.S.C. §120 of commonly-owned, U.S. patentapplication Ser. No. 09/257,844, now U.S. Pat. No. 6,248,954 B1,entitled, Multi-Pair Data Cable with Configurable Core Filling and PairSeparation, filed Feb. 25, 1999, which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to high-speed data communications cablesusing at least two twisted pairs of insulated conductors. Moreparticularly, the invention relates to high-speed data communicationscables having a light-weight, configurable core-refilling isolation pairseparator that provides geometrical separation between the twisted pairsof insulated conductors.

DISCUSSION OF THE RELATED ART

High-speed data communications media in current usage include pairs ofinsulated conductors twisted together to form a balanced transmissionline. Such pairs of insulated conductors are referred to herein as“twisted pairs.” When twisted pairs are closely placed, such as in acable, electrical energy may be transferred from one twisted pair of acable to another twisted pair. Such energy transferred between twistedpairs is referred to as crosstalk. As operating frequencies increase,improved crosstalk isolation between the twisted pairs becomes morecritical.

The Telecommunications Industry Association and the Electronics IndustryAssociation (TIA/EIA) have developed standards which specify specificcategories of performance for cable impedance, attenuation, skew andparticularly crosstalk isolation. One standard for crosstalk or, inparticular, crosstalk isolation, is TIA/EIA-568-A, wherein a category 5cable is required to have 38 dB of isolation between the twisted pairsat 100 MHz and a category 6 cable is required to have 42 dB of isolationbetween the twisted pairs at 100 MHz. Various cable design techniqueshave been used to date in order to try to reduce crosstalk and toattempt to meet the industry standards.

For example, one cable implementation known in the industry that hasbeen manufactured and sold as a high-speed data communications cable,includes the twisted pairs formed with relatively tight twists, and thecable is formed into a round construction. In this conventional cable,each twisted pair has a specified distance between twists along alongitudinal direction of the twisted pair, that distance being referredto as the “twist lay.” When adjacent twisted pairs have the same twistlay and/or twist direction, they tend to lie within a cable more closelyspaced than when the twisted pairs have different twist lays and/or adifferent twist direction. Such close spacing increases the amount ofundesirable crosstalk which occurs between the twisted pairs. In someconventional cables, each twisted pair within the cable has a uniquetwist lay in order to increase the spacing between pairs and thereby toreduce the crosstalk between twisted pairs of the cable. In addition,the twist direction of the twisted pairs may also be varied. However,this industry standard configuration can only achieve limited crosstalkisolation.

Another cable implementation 100 disclosed in U.S. Pat. No. 4,777,325,is illustrated in FIG. 1, wherein the twisted pairs are enclosed withina jacket 102 that has a wide, flat configuration. In particular, aplurality of twisted pairs 104 a-104 b, 106 a-106 b, 108 a-108 b, and110 a-110 b are positioned side-by-side, each in separate compartments112, 114, 116, and 118 formed within a flat hollow envelope of anextruded outer sheath 120. The cable is provided with separator ribs 122between a top and a bottom of the sheath to divide the outer sheath intothe separate compartments and to prevent lateral movement of the twistedpairs out of their respective compartments. However, one problem withthis flat configuration for a cable is that it has limited flexibilityas compared to that of a round cable, which hinders installation of thecable in conduits and around bends.

Another cable implementation which addresses the problem of twistedpairs lying too closely together within the cable is described, forexample, in U.S. Pat. No. 5,789,711 and is illustrated in FIG. 2. Inparticular, the cable includes, for example, four twisted pairs 124disposed about a central pre-shaped support 126, wherein the supportpositions a twisted pair within grooves or channels 128 formed by thesupport. In particular, the support provides the grooves or channelswhich keep the twisted pairs at fixed positions with respect to eachother. The support can have any of a number of shapes, including, forexample, a standard “X”, a “+”, or the separator as is illustrated inFIG. 2. The prongs or protrusions 130 of the support preserve thegeometry of the pairs relative to each other, which helps reduce andstabilize crosstalk between the twisted pairs. However, some problemswith the support is that the support adds cost to the cable, may limitthe flexibility of the cable and increases the size; e.g., the diameter,of the cable. Another problem may be that the material which forms thesupport may result in the overall cable being a potential fire and/orsmoke hazard.

Still another known industry cable implementation 132 is illustrated inFIG. 3. The cable utilizes a jacket 134 with inward protrusions 136 thatform channels 138 within the cable. A twisted pair 140 of conductors142, 144 is disposed within each channel. The protrusions are used toprovide adequate pair separation. However, one problem with theseprotrusions is that they can be difficult to manufacture. In addition,the protrusions may not provide adequate separation between the twistedpairs where the stability of the protrusions is difficult to provide,and thus performance repeatability of the cable is an issue. Further,another problem is that the jacket is not easily strippable. When thecable is to be stripped by removing the outer jacket, which is oftendone with a sharp device such as, for example, a razor, the protrusionswill not be cut by the incision around the circumference of the jacketand will have to be broken off separately in order to remove the jacket.

Accordingly, some of the problems with the above known configurationsare that they are expensive, difficult to use, are generally undesirablylarge, and have decreased flexibility of the cables and workability ofthe twisted pairs of wires.

SUMMARY OF THE INVENTION

Therefore, a need exists for a high-speed data cable having multipletwisted pair wires with desired crosstalk performance, improved handlingand termination capabilities, that is inexpensive, flexible and has adesired size. This invention provides an improved data cable.

According to the invention, a data communications cable has beendeveloped so as to better facilitate the cable for its the intended useof high speed data transmission, yet maintain a form factor that hasdesired flexibility and workability, and that is compatible withindustry standard hardware, such as plugs and jacks. The datacommunications cable of the invention has the additional benefit of areduced cabled size relative to other known cables within itsperformance class.

In particular, the present invention provides these advantages byutilizing a substantially flat configurable, highly flexible,core-filling, dielectric separator to provide twisted pair separationfor the cable.

One embodiment of a data communications cable of the invention includesa first twisted pair of insulated conductors, a second twisted pair ofinsulated conductors, and the substantially flat dielectric pairseparator. The substantially flat configurable dielectric pair separatoris disposed between the first twisted pair of insulated conductors andthe second twisted pair of insulated conductors The data communicationscable also includes a jacket assembly enclosing the first twisted pairof insulated conductors, the second twisted pair of insulatedconductors, and the substantially flat dielectric pair separator.

With this arrangement, the data communications cable can be made withdesired crosstalk isolation between the twisted pairs of insulatedconductors. In addition, due to the conforming nature and the desiredthickness of the substantially flat configurable dielectric pairseparator, the cable has desired flexibility, workability and size.Moreover, these advantages do not come at the expense of otherproperties of the cable such as, for example, size or reduced impedancestability. The substantially flat configurable dielectric pair separatoralso facilitates termination of the data communications cable to knownindustry standard hardware.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the present invention willbecome more apparent in view of the following detailed description ofthe invention when taken in conjunction with the figures, in which:

FIG. 1 is a perspective view of an embodiment of a communications cableaccording to the related art;

FIG. 2 is a cross-sectional view of another embodiment of acommunications cable according to the related art;

FIG. 3 is a cross-sectional view of another embodiment of acommunications cable according to the related art;

FIG. 4 is a perspective view of a data communications cable according toone embodiment of the invention;

FIG. 5 is a cross-sectional view of the embodiment of the datacommunications cable of FIG. 4;

FIG. 6 is a cross-sectional view of a data communications cableaccording to another embodiment of the invention;

FIG. 7 is a cross-sectional view of a data communications cableaccording to another embodiment of the invention;

FIG. 8 is a cross-sectional view of a data communications cableaccording to another embodiment of the invention;

FIG. 9 is a cross-sectional view of a data communications cableaccording to another embodiment of the invention;

FIG. 10 is a cross-sectional view of a data communications cableaccording to another embodiment of the invention;

FIG. 11 is a cross-sectional view of a data communications cableaccording to another embodiment of the invention;

FIG. 12 is a perspective view of a system for practicing a method ofmaking a cable in accordance with an embodiment of the invention;

FIG. 13A illustrates a core of a four twisted pair cable; and

FIG. 13B is an exploded view of the core of the cable of FIG. 13A,having a filler material according to the invention.

DETAILED DESCRIPTION

A number of embodiments of a data communications cable according to theinvention will now be described in which the cable is constructed with aplurality of twisted pairs of insulated conductors and a core made froma configurable, dielectric pair separator. However, it is to beappreciated that the invention is not limited to any number of twistedpairs or any profile for the configurable, dielectric pair separatorillustrated in any of these embodiments. The inventive principles can beapplied to cables including greater or fewer numbers of twisted pairsand having different core profiles of the configurable dielectric pairseparator. In addition, although these embodiments of the invention aredescribed and illustrated in connection with twisted pair datacommunication media, it is to be appreciated that other high-speed datacommunication media can be used instead of twisted pairs of conductorsin the constructions of the cable according to the invention, such as,for example, fiber optic media.

FIG. 4 depicts an embodiment of a data communications cable 10 accordingto the present invention. The cable 10 includes two twisted pairs 12 ofinsulated conductors 13. The twisted pairs 12 are separated by a lowdielectric constant, low dissipation factor, polymer “pair separator”14. The twisted pairs 12 and the pair separator 14 are encased within ajacket assembly 16. The outer jacket can be a PVC, a low-smoke,low-flame PVC, or any plenum or non-plenum rated thermoplastic.

FIG. 5 depicts a cross-sectional view of an embodiment of the cable ofFIG. 4. The configurable pair separator 14 runs along a longitudinallength of the cable, and is configured such that the twisted pairs aredisposed within channels or grooves 15 of the pair separator along thelength of the cable. As illustrated, the grooves 15 do not formcompletely enclosed channels. Some of the advantages of this cableaccording to the invention are that the pair separator providesstructural stability during manufacture and use of the datacommunications cable, yet does not degrade the flexibility andworkability of the cable, and does not substantially increase the sizeof the cable. In addition, the pair separator improves the crosstalkisolation between the twisted pairs by providing desired spacing betweenthe twisted pairs. Therefore, the configurable pair separator of theinvention lessens the need for complex and hard to control twist layprocedures, core filling arrangements and jacket embodiments describedabove with respect to the related art.

The above-described embodiment of the data communications cable can beconstructed using a number of different materials as the pair separator14. While the invention is not limited to the materials describedherein, the invention is advantageously practiced using these materials.In particular, the configurable pair separator is preferably aflame-retardant, low-dielectric constant, low-dissipation factor, foamedpolymer tape, such as, for example, a foamed flame retardant, cellularpolyolefin or fluoropolymer like NEPTC PP500 “SuperBulk”, a foamedfluorinated ethylene propylene (FEP) or a foamed polyvinyl chloride(PVC). The above-described pair separators are preferably used in anon-plenum rated application where the cable is not required to passindustry standard flame and smoke tests such as the UnderwritersLaboratories (UL) 910 test. Another preferable configurable pairseparator is a woven fiberglass tape normally used as a binder forcables, such as, for example, Allied Fluoroglass CTX3X50. This wovenfiberglass binder is preferably used in a plenum rated application wherethe cable must satisfy the UL 910 test.

Still another pair separator material that may be used in the cable ofthe invention is a bulk filling material such as a polyolefin or glassfiber filler that is flame-retardant and is typically shredded orfibrulated, but may also be solid, such as, for example, Chadwick AFT033 Fiberglass. Such a bulk filling material is typically twisted up andused as a filling material in a core of the cable, with no otherpurpose. In particular, referring to FIG. 13A, the bulk filler istypically used as a core filling material that fills 100% of the corearea 50 between the illustrated four twisted pair, that is used to keepthe cable in a more or less round construction. However, referring toFIG. 13B, according to the present invention it is preferable to provideless than 100% of the core area 50 with the filling material; and it ismore preferable us use less than 42% of the core with the fillermaterial 52 for providing isolation between the twisted pairs. In apreferred embodiment, approximately 32% of the overall core area betweenthe four twisted pairs of the cable is filled with such a filler andshaped as described herein. Therefore, one aspect of the presentinvention is the recognition that the filler or tape described above canbe used to prevent physical contact between opposite and adjacenttwisted pairs, thereby increasing the isolation between the twistedpairs, while not requiring the entire core area be filled, and thereforenot sacrificing the size, cost or flexibility of the overall cable.

FIG. 6 depicts a cross-sectional view of a preferred embodiment of thedata cable 10 of this invention. The cable includes the low-dielectricconstant, low-dissipation factor polymer pair separator 14 formed into acable core in such a way as to physically separate the four twistedpairs 12, thereby decreasing field coupling between the twisted pairs,providing a desired opposite twisted pair-to-pair physical distance, aswell as providing a desired adjacent pair separation. It is to beappreciated that like components of the data communications cableillustrated in FIGS. 4-5 have been provided with like reference numbersand the description of these components applies with respect to each ofthe cable embodiments to be described herein.

In the embodiment of the cable of FIG. 6, the pair separator 14 is aflat configurable tape used as a core filler, that is shaped to have theillustrated profile and that is provided in the cable between the fourtwisted pairs 12. In particular, in this embodiment, the configured pairseparator has a shape somewhat like a “+”, providing four channels 15between each pair of protrusions 17 formed by the pair separator. Eachchannel carries one twisted pair 12 that is placed within the channelduring a process of manufacturing the cable that will be described infurther detail below. As is discussed above, the illustratedconfigurable core profile should not be considered limiting. Inparticular, although it is preferred that the pair separator is suppliedas a flat extruded tape, the configurable pair separator may be made bya process other than extrusion and may have a number of different shapesor provide a number of different channels, as is illustrated by some ofthe embodiments described in further detail below.

Referring again to FIG. 6, the data communications cable may also beprovided with a binder 19, as illustrated in phantom, that is wrappedaround the configurable core pair separator 14 and the plurality oftwisted pairs 12. For this embodiment, it is preferable that theconfigurable core pair separator be an aluminum/mylar tape, with analuminum layer on a side of the tape facing the plurality of twistedpairs. In addition, it is preferred that the binder be made of thealuminum/mylar tape, with the aluminum layer of the tape facing theplurality of the twisted pairs so that the combination of the binder andthe configurable pair separator provide four electrically shielded,enclosed channels. With this embodiment, the four enclosed channels areisolated from one another to provide desired crosstalk isolation. Inaddition, another benefit of the embodiment of the cable is that a cableadjacent this cable will have reduced coupling with the cable of theinvention, or in other words, reduced alien cross talk as it is known inthe industry.

The embodiment of FIG. 6 further illustrates a shield 21 may also belaterally wrapped around the binder 19; the shield is preferably madefrom a foil or metal. The shield may be applied over the cable beforejacketing the cable with the jacket 16, and is also used to help reducecrosstalk between the twisted pairs, to reduce alien crosstalk, andprevent the cable from causing or receiving electromagneticinterference. It is to be appreciated that the shield can also beprovided in lieu of the binder. In particular, greater crosstalkisolation between the twisted pairs of the cable, and reduced aliencrosstalk may also be achieved by using a conductive shield 21 that is,for example, a metal braid, a solid metal foil, or a conductive plasticthat is in contact with ends of the protrusions 17 of the configurablefiller 14. If the configurable pair separator is also conductive orsemi-conductive as described above for the aluminum/mylar tape, then thecombination of the pair separator and the shield forms conductivecompartments that shield each twisted pair from the other twisted pairs.Referring to FIG. 6, the cable can advantageously include a metal drainwire 23 exposed, for example, within the middle of the configurable pairseparator 14. The metal drain wire runs the length of the cable and actsas a ground. However, it is to be appreciated that the metal drain wireneed not be so placed and may also be arranged in arrangements known tothose of skill in the art such as, for example, spirally wrapped aroundthe binder 19 or the shield 21.

It is preferable in the embodiments described herein that theprotrusions 17 of the configurable pair separator extend at least beyonda center axis of each twisted pair, known in the art as a pitch radius.The pitch radius is illustrated in FIG. 6 as the radius R between thecenter of the cable core and the center axis of the twisted pairs 12 ofconductors. This preferred configuration of the configurable pairseparator ensures that the twisted pairs do not escape their respectivespaces or channels. It is also to be appreciated that the process ofjacketing of the cable, to be described in detail below, may bend theends of the protrusions 17 over slightly (not illustrated), since theconfigurable pair separator is relatively formable.

As discussed above, it is to be appreciated that the twisted pairs ofinsulated conductors and configurable pair separator of thecommunications data cable of the invention, can be configured in avariety of ways. FIGS. 7-12 depict cross-sectional views of variousembodiments of the data communications cable of the invention. Asillustrated, for example, in FIGS. 7, 9 and 10, the configurable pairseparator may be configured such that the grooves 15 do not formcompletely enclosed channels. FIG. 7 depicts a cable 10 wherein sixtwisted pairs 12 are encased within the jacket assembly 16, and areseparated from each other by the configurable pair separator 14. Thepair separator 14 is configured in a somewhat “*” shape that providessupport and placement of the twisted pairs so that the twisted pairs 12have a desired spacial arrangement and do not come into direct physicalcontact with each other.

FIG. 8 depicts still another embodiment of the data communications cable10 having multiple twisted pairs 12 encased within the jacket assembly16 and having at least one of the twisted pairs isolated by the pairseparator 14, from the remainder of the twisted pairs. In particular,referring to FIG. 8, the twisted pairs have been labeled TP1, TP2, TP3and TP4, wherein twisted pair TP4 is isolated from twisted pairs TP1,TP2 and TP3 by the pair separator 14. It is an advantage of thisembodiment, that the pair separator 14 can be provided with anappropriate number of twists or wrappings around the twisted pair TP4,so as to provide selective isolation between twisted pair TP4 andtwisted pairs TP1, TP2 and TP3. This embodiment of the cable accordingto the invention can be used, for example, to provide better isolationbetween a weakest one or a weakest combination of twisted pairs ofcables, in an environment where there is known to be a low amount ofisolation between a particular twisted pair and another twisted pair, ora plurality of twisted pairs. Accordingly, with this embodiment of thecable of the invention, there can be selective enhancement of isolationbetween twisted pairs TP1-TP4, TP2-TP4, and TP3-TP4. It is to beappreciated that although the twisted pair TP4 has been illustrated asbeing isolated from the remainder of the twisted pairs, that any of thetwisted pairs can be so wrapped with the filler and isolated. Thisembodiment of the invention may also be used in conjunction with alessening of the twist lays requirements for the twisted pairs, toprovide cable having a same amount of isolation between twisted pairs asa cable with tighter twist lays. Accordingly, this embodiment of thecable according to the invention allows for selective design ofisolation between particular twisted pairs of the cable and lessening ofthe twist lay requirements for the cable.

FIG. 9 depicts still another embodiment of the data communications cable10 having multiple twisted pairs 12 encased within the jacket assembly16 and physically separated from each other by the configurable pairseparator 14, and also including a central core filler 18 positioned atthe middle of the cable and that runs along the longitudinal length ofthe cable, provided less than 100% of the core is filled with thefiller. The configurable pair separator provides desired separationbetween the individual twisted pairs 12 as discussed above. The centralcore 18 provides additional support or structure and may be formed of,for example, a solid or foamed flame retardant polyolefin or othermaterials that are known in the industry. For plenum rated cables, it ispreferable that the core be any of one or more of the followingcompounds: a solid low-dielectric constant fluoropolymer, e.g. ethylenechlorotrifluoroethylene (E-CTFE), FEP, a foamed fluoropolymer, e.g.foamed FEP, and PVC in either solid, low dielectric constant form orfoamed. The central core filling 18 may also be constructed of the samematerials as the configurable pair separator 14 discussed above.

FIG. 10 depicts yet another embodiment of a data communications cable10, having a substantially flat configuration. Twisted pairs 12 areencased within a substantially flat jacket assembly 16 and physicallyseparated from each other by the configurable pair separator 14. Thecable of FIG. 10 is an alternative to the cable of the related art asillustrated in FIG. 1, and other known flat cables. It is to beunderstood, that although this embodiment is illustrated with a singlefold of the pair separator material between each twisted pair, that thenumber of folds can be increased to further adjust the distance betweeneach of the twisted pairs and thereby increase the isolation betweeneach of the twisted pairs. Other variations known to those of skill inthe art are also intended to be within the scope of the invention andthis embodiment. For example, the pair separator may also be disposed ata bottom of the cable with folds directed upwardly towards the top ofthe cable, in contrast to at the top of the cable with the foldsdirected towards the bottom of the cable as illustrated in FIG. 10, orthe pair separator may be disposed at both the bottom and top.

FIG. 11 depicts an embodiment of a data communications cable 22including a plurality of data communications cables 10 according to anyof the embodiments described above. In particular, each data cable 10contains multiple twisted pairs 12 separated by the configurable pairseparator 14 according to any of the above-described configurations, andencased in the jacket assembly 16. The plurality of data cables areenclosed within outer casing 20. The cable 22 may also have a centralcore filler 24, as illustrated in phantom, that may be formed from anyof the above-described materials and may be used to, for example, tokeep the data cables in a desired arrangement so as to, for example,minimize crosstalk between each of the data cables 10.

Referring now to FIG. 12, there is illustrated a perspective view of asystem for practicing a method of making a cable in accordance with anembodiment of the invention. The pair separator 26 is drawn from a reelor pad (not shown), and is formed around a round cob 28 into a shapedpair separator such as, for example, in the shape of a cylinder. Theshaped pair separator is aligned with four twisted pairs 12 by passingthe four twisted pairs through openings 30 in first die 32, and theshaped pair separator through central opening 34. The shaped pairseparator is then further configured into a desired shape (formed pairseparator) as illustrated in FIG. 12. It is to be appreciated, asdiscussed above, that this shape can be varied. The formed pairseparator 15 is then passed through opening 36 in second die 38 andbrought together with the four twisted pairs 12 which are passed throughcorresponding openings 40 in the second die. The plurality of twistedpairs are then cabled with the formed pair separator by a third die 42,in an operation referred to as “bunching”. The third die places thetwisted pairs in the channels 15 (see FIGS. 5-10) of the formed pairseparator prior to twisting of the cable. It is to be appreciated thatthe cable can be twisted with any known twisting arrangement such as ahelix, or an S-Z configuration. It is also to be appreciated that thismethod can be varied to include any of the components illustrated anddiscussed above, such as, for example, to include a drain wire, abinder, a shield, or central core filler.

Accordingly, some of the advantages of the various embodiments of thedata communications cable of the invention are crosstalk performance andisolation enhancement can be configured and provided as customized cablesolutions for hardware manufactures who request special requirements.For example, specific twisted pair combinations can receive a dedicatedamount of isolation tape folds, thereby enhancing separation of selectedtwisted pairs and enhancing crosstalk isolation between the selectedtwisted pairs where an end user, for example, needs more crosstalkisolation. The data communications cable can also be made with a desiredcrosstalk isolation between the opposing twisted pairs of insulatedconductors. In addition, due to the conforming nature and the thicknessof the pair separator material, this advantage does not come at theexpense of, for example, the size of the data communications cable, anddoes not result in a reduced impedance stability of the datacommunications cable. Another advantage is that the amorphous nature ofthe pair separator yields a desired cable that better facilitatestermination of the data communications cable to known industry hardware,than larger diameter cables of the related art.

The present invention has now been described in connection with a numberof specific embodiments thereof. However, numerous modifications whichare contemplated as falling within the scope of the present inventionshould now be apparent to those skilled in the art. Therefore, it isintended that the scope of the present invention be limited only by thescope of the claims appended hereto.

1. A finished communications cable comprising: a plurality of twistedpairs of insulated conductors comprising a first twisted pair ofinsulated conductors and a second twisted pair of insulated conductors;a substantially flat configurable dielectric separator disposed betweenthe plurality of twisted pairs of conductors in the finishedcommunications cable, that separates the first twisted pair of insulatedconductors from the second twisted pair of insulated conductors; and ajacket enclosing the plurality of twisted pairs of insulated conductorsand the configurable dielectric separator; wherein the plurality oftwisted pairs of insulated conductors and the substantially flatconfigurable dielectric separator are twisted about a common axis toform the finished communications cable.
 2. The communications cable asclaimed in claim 1, wherein the substantially flat configurabledielectric separator is arranged to have no more than one concavesurface to provide a groove extending along a longitudinal length of thecommunications cable.
 3. The communications cable as claimed in claim 1,wherein the substantially flat configurable dielectric separator isarranged within the jacket to provide at least two grooves, at least onetwisted pair of insulated conductors being disposed within each of theat least two grooves.
 4. The communications cable as claimed in claim 1,wherein the substantially flat configurable dielectric separatorincludes a foamed polymer.
 5. The communications cable as claimed inclaim 1, wherein the substantially flat configurable dielectricseparator includes a woven fiberglass tape.
 6. The communications cableas claimed in claim 1, wherein the substantially flat configurabledielectric separator includes a flame-retardant, low-dielectricconstant, foamed polymer tape.
 7. The communications cable as claimed inclaim 1, wherein the substantially flat configurable dielectricseparator includes a foamed fluorinated ethylene propylene material. 8.The communications cable as claimed in claim 1, wherein thesubstantially flat configurable dielectric separator is aflame-retardant, foamed polymer tape.
 9. The communications cable asclaimed in claim 1, further comprising a central core filling materialdisposed in a core of the communications cable between the first andsecond twisted pairs of insulated conductors.
 10. The communicationscable as claimed in claim 9, wherein the central core filling is made ofa same material as the substantially flat configurable dielectricseparator.
 11. The communications cable as claimed in claim 1, furthercomprising a conductive shield substantially surrounding the pluralityof twisted pairs of insulated conductors and the substantially flatconfigurable dielectric separator.
 12. The communications cable asclaimed in claim 1, wherein the substantially flat configurabledielectric separator is arranged so as to separate each twisted pair ofinsulated conductors from every other twisted pair of insulatedconductors.
 13. The communications cable as claimed in claim 1, whereinthe substantially flat configurable dielectric separator comprises aconductive layer and is arranged so that the conductive layer faces eachof the plurality of twisted pairs of insulated conductors.
 14. Thecommunications cable as claimed in claim 1, wherein the substantiallyflat configurable dielectric separator comprises an aluminum/mylar tape,an aluminum layer of the aluminum/mylar tape facing the plurality oftwisted pairs of insulated conductors.
 15. The communications cable asclaimed in claim 1, wherein the substantially flat configurabledielectric separator is arranged to provide a sufficient spacing betweenthe first twisted pair of insulated conductors and the second twistedpair of insulated conductors so as to provide a desired crosstalkisolation between the first twisted pair of insulated conductors and thesecond twisted pair of insulated conductors.
 16. The communicationscable as claimed in claim 1, wherein the substantially flat configurabledielectric separator is arranged so as to prevent the first twisted pairfrom contacting the jacket.
 17. The communications cable as claimed inclaim 1, wherein the substantially flat configurable dielectricseparator has a concave shape.
 18. The communication cable as claimed inclaim 17, wherein the substantially flat configurable dielectricseparator does not extend more than 180 around any one of the pluralityof twisted pairs of insulated conductors.
 19. An unshieldedcommunications cable comprising: a plurality of twisted pairs ofinsulated conductors comprising a first twisted pair of insulatedconductors and a second twisted pair of insulated conductors; asubstantially flat configurable dielectric separator that consists ofnon-conductive, dielectric materials disposed between the plurality oftwisted pairs of conductors that separates the first twisted pair ofinsulated conductors from the second twisted pair of insulatedconductors; and a jacket enclosing the plurality of twisted pairs ofinsulated conductors and the configurable dielectric separator; whereinthe substantially flat configurable dielectric separator includes afoamed polymer.
 20. The communications cable as claimed in claim 19,wherein the substantially flat configurable dielectric separatorincludes a flame-retardant, low-dielectric constant, foamed polymertape.
 21. The communications cable as claimed in claim 19, wherein thesubstantially flat configurable dielectric separator includes a foamedfluorinated ethylene propylene material.
 22. The communications cable asclaimed in claim 19, wherein the substantially flat configurabledielectric separator is a flame-retardant, foamed polymer tape.